Entropic disorder at the BBC

The second programme in the Genius of Invention series was mainly up to the usual high BBC documentary standard. The Lad returned to it following his review of the first of the series.

Most of his original thoughts this time were, in truth, nit-picking: why the presenters were gurning so much with their continual, strained grins, indeed why were there three presenters at all . On the latter, the producers presumably wanted to avoid the unthinkably, unfashionable, single lecturer. Mostly though here the jump cut effect is mere hyper-activity. As well, there seems no logic in having an “industrial archaeologist” who shows little archaeology but does instruct another presenter on certain simplistic features of a modern jet engine.

Then the Lad realised that something had almost passed him by with only a momentary feeling of something wrong. There was a programme segment on Nicolas Sadi Carnot that sought to discuss the efficiency of steam engines. He went back to review it and was amazed.

Neither of the two presenters involved even mentioned the central point that, in any and all engines, heat must be rejected for them to produce power. That is not difficult to tell. It led to the Second Law of Thermodynamics: probably one of the most important things that humanity has learnt about the operation of the universe. This is what we have to thank Carnot for.

Instead it offered a model engine that was, frankly, laughable. Not because it was solely two lengths of plastic guttering rather than piston and cylinder. That is of no concern. One problem was that it was not even any sort of analogue. Then there were a ridiculous trio of jars each with a different amount of coloured water and given wrong descriptions. It was more like the sleight of hand that is the huckster’s Shell Game.

There was mention of an ‘ideal engine’. There were leaks said to represent energy losses due ‘waste heat’, ‘bearings’, ‘friction’ and ‘noise’. Most of these losses, in the real world, illustrated the First Law of Thermodynamics rather than the phenomenon that was Sadi Carnot’s insight.

The whole segment cast no light on Carnot’s insights; indeed it instructed the viewer wrongly. What was Professor Mark Miodownik thinking about associating himself with this train crash of a presentation?

The Second Law of Thermodynamics is central to the practice of real engineering, but this segment added nothing to the story linking Stephenson and Otto and Benz and Whittle. It should have been left out. Putting it in damaged the credibility of the whole programme.

Engineering is one of the three drivers advancing the human race. This blog describes real professional engineering as it is in the real world. It is not well served by the current media. An engineer is posting: not a ‘scientist’. The Lad is entirely independent of any organisation mentioned. The target of the blog is the career seeker and the general public.



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